Waccamaw Drainage Fishes 19 



Winyah Bay forms an effective barrier limiting faunal exchange between 

 the two rivers, at least for most of the freshwater forms. Therefore, we 

 argue that the Waccamaw should be viewed as a separate drainage that 

 limits dispersal of most primary freshwater fishes. A similar situation 

 exists between the Chowan and Roanoke Rivers, where the Chowan 

 enters the Roanoke drainage in the estuarine habitat of Albemarle 

 Sound. According to Jenkins et al. (1972) there is "some merit in con- 

 sidering it (the Chowan) a separate drainage." 



Fifty-six species of freshwater and diadromous fishes were collected 

 from the Waccamaw drainage during our survey. These include four 

 families of secondary freshwater fishes (Lepisosteidae, Cyprinodontidae, 

 Poeciliidae and Atherinidae), and four families of diadromous fishes 

 (Anguillidae, Clupeidae, Percichthyidae, and Soleidae), with the remain- 

 ing ten families representing primary freshwater forms (mostly after 

 Myers 1938). Most of the secondary freshwater and diadromous species 

 behave as primary forms, and two — Fundulus waccamensis and Menid- 

 ia extensa — are known only from fresh water. Nine additional 

 species — Alosa sapidissima, Dorosoma petenense, Notropis hudsonius, 

 N. hypselopterus, Ictalurus melas, I. punctatus, Fundulus chrysotus, F. 

 diaphanus and Morone saxatilis — have been reported (various sources 

 listed in text) from the Waccamaw River and tributaries. Of these, Fun- 

 dulus chrysotus and F. diaphanus have been examined and verified by 

 us. Alosa sapidissima, Notropis hudsonius, Ictalurus punctatus and 

 Morone saxatilis were not verified, but probably do occur. It is doubtful 

 that the remaining three species — Dorosoma petenense, Notropis hyp- 

 selopterus, and Ictalurus melas — are found in this drainage. Compared 

 to other small Atlantic Coastal Plain drainages, the Waccamaw drain- 

 age has an unusually high species diversity (Table 2). This can be partly 

 attributed to the lentic habitats of Lake Waccamaw, from which 44 spe- 

 cies have been collected by us or otherwise reported. 



The Waccamaw and Little Pee Dee (Big Swamp and Lumber sys- 

 tems) once occupied a much larger basin draining areas of the inner 

 Coastal Plain and Piedmont. Approximately 75,000 years ago the uplift 

 of the Cape Fear Fault (roughly paralleling the Cape Fear River) 

 resulted in elevation of land southwest of the Cape Fear River and sub- 

 sequent pirating of the upper parts of the Waccamaw and Little Pee 

 Dee systems by the Cape Fear (Zullo and Harris 1979). Stream flow was 

 diverted along this fault to form the Cape Fear River, leaving the Wac- 

 camaw and Little Pee Dee systems with greatly reduced drainage basins 

 confined largely to the Coastal Plain. Zoogeographic evidence also sug- 

 gests a close relationship between these drainages. Three species of fish 

 are shared exclusively by the Cape Fear and Pee Dee drainages: Semoti- 

 lus lumbee, Sandhills chub (Snelson 1980); Hybopsis species, thinlip 

 chub (Jenkins and Lachner 1980); and Noturus species, broadtail mad- 

 torn (Jenkins and Palmer 1978). However, only one of these, the broad- 



